1. Field of the Invention
The present invention relates to a pin jet nozzle, or fog nozzle, for use in a pressurized evaporative cooling system. In particular, the present invention relates to an improved pin jet nozzle adapted for use in providing an evaporative fog consisting essentially of fluid particles having a diameter of less than fifty micrometers (50 .mu.m.), said nozzle comprising:
a. a base portion itself comprising: PA1 b. a pin portion itself comprising: PA1 c. further comprising a nozzle insert comprising: PA1 It is a completely different magnitude--an oil burner does not require droplets having a particle size of the present invention; PA1 It is an atomizing nozzle--the flow is swirled around internally, giving the particles a high tangential velocity, to create the greatest possible dispersion and mixing with the air--therefore, an efficient combustion. PA1 It is a high temperature environment--the oil coming from the nozzle is burned. PA1 The Huss reference deals with a different alignment problem--the alignment problem in the Huss reference is internal, and has nothing to do with the orifice insert. PA1 The wear problem the Huss reference addresses is different--hardly surprising that a high-molecular weight oil with various impurities, at high tangential velocities in a high-temperature environment, would create a wear problem on the orifice. PA1 The nozzle of the Huss reference is not a fog nozzle--It is doubtful if the pieces could be made on the scale of a fog nozzle (particularly the diamond insert), or that a fog would result if it were to be done. PA1 a. a base portion itself comprising: PA1 b. a pin portion itself comprising: PA1 c. further comprising a nozzle insert comprising:
i. means for connection of said nozzle to a pressurized hydraulic system; PA2 ii. means for receiving fluid from said system; and, PA2 iii. an orifice component, said orifice component comprising: PA2 i. support and centering means; and, PA2 ii. an impingement pin member mounted upon said support and centering means and positioned over said outlet orifice and having an impingement face in the path of said fluid jet which is substantially similar in dimension to the diameter of said fluid jet; PA2 i. an insert member comprising a hollow, generally cylindrical insert adapted to be held firmly within the outlet orifice of said base portion; and, PA2 ii. an orifice member held firmly within the generally cylindrical insert member, which orifice member comprises: PA2 i. means for connection of said nozzle to a pressurized hydraulic system; PA2 ii. means for receiving fluid from said system; and, PA2 iii. an orifice component, said orifice component comprising: PA2 i. support and centering means; and, PA2 ii. an impingement pin member mounted upon said support and centering means and positioned over said outlet orifice and having an impingement face in the path of said fluid jet which is substantially similar in dimension to the diameter of said fluid jet; PA2 i. an insert member comprising a hollow, generally cylindrical insert adapted to be held firmly within the outlet orifice of said base portion; and, PA2 ii. an orifice member held firmly within the generally cylindrical insert member, which orifice member comprises:
A. an inlet adapted to receive fluid from said system; PA3 B. a outlet orifice for the release of fluid from said system in the form of a jet; and, PA3 C. a delivery channel adapted to convey fluid from said inlet to said outlet orifice; and, PA3 A. a wear-resistant material; PA3 B. a central orifice with a diameter of from about three one-thousandths of an inch (0.003 in.) to about fifteen one-thousandths of an inch (0.015 in.); and, PA3 C. a high degree of concentricity, with a variance in the concentricity of said central orifice of less than five ten-thousandths of an inch (0.0005 in.). PA3 A. an inlet adapted to receive fluid from said system; PA3 B. an outlet orifice for the release of fluid from said system in the form of a jet; and, PA3 C. a delivery channel adapted to convey fluid from said inlet to outlet orifice; and, PA3 A. a wear-resistant material; PA3 B. a central orifice with a diameter of from about three one-thousandths of an inch (0.003 in.) to about fifteen one-thousandths of an inch (0.015 in.).
2. Description of Related Art
Evaporative cooling systems have been employed in various applications for a number of years. Such systems typically involve a pressurized fluid, usually water, escaping through a small orifice and impinging on a proximate surface. The force of the pressurized stream against the proximate surface causes the fluid to disperse into minute particles creating a localized fog. A fog differs from a mist, although the terms are often used imprecisely. As used herein, a fog contains small droplets which evaporate from the air rather than falling to cause a localized wetting. Fogs are typically used for cooling, and sometimes, for humidification. A mist, as used herein, contains larger particles which fall to create a localized wetting, and are typically used more for providing irrigation.
Because of the difficulty in precisely cutting the small diameter orifice and delivery channel, such prior art nozzles have typically been formed from brass and other relatively soft metals because of the difficulty in working. Recently, some nozzles have been produced in stainless steel, however, such nozzles still follow the design of previous nozzles.
The short delivery channels of the prior art appeared to be necessary because of the limitations of metalworking. Cutting a narrow orifice, typically on the order of six one-thousandths of an inch (0.006 inch), is typically done with a pin drill, usually a stationary drill which engages rotating work. The depth which can be achieved with such a metalworking procedure, typically no greater than fifteen-thousandths of an inch (0.015 inch), is chiefly a function of how well the drill bit can be supported during the metal working process.
Further, and perhaps more important to the present invention, the nature of the metalworking employed to cut the orifice and delivery channel is such that the concentricity of the orifice and the integrity of the orifice and channel walls is difficult to maintain. The drilling operation is known to gouge and scar the interior surface of the delivery channel and leave an imprecise mouth to the orifice itself.
These problems were addressed in U.S. Pat. No. 4,869,430 to Good. That reference teaches the use of an insert cut from a length of stainless steel surgical tubing. While this reference overcomes many of the difficulties of the prior art, the internal diameter of such tubing is not always dimensionally accurate, and the metalworking of the cut ends of the tubing sometimes distorts the mouth of the orifice. Further, the extrusion process which draws such tubing is primarily concerned with the outside diameter of the finished tubing, and the inside diameter is often imprecise, with fluting and a lack of concentricity being common problems. Such fluting can cause collection of debris, while a lack of concentricity causes a variance in spray patterns. In either case, the variable flow which resulted from piece to piece variations meant that system flow volumes could not be accurately predicted.
Even with the improvements taught in the Good reference, however, it has been difficult, if not impossible, to predict the flow requirements of a system where a plurality of nozzles of different flow rates are employed. Such a situation has rendered it difficult to design efficient spray patterns and regular flow levels.
A pin-jet nozzle is used in a hydraulic system in which the water is pressurized to about 350 to 500 pounds per square inch. At that pressure a thin, substantially-coherent stream of water is forced out through an orifice which is a hole approximately six one-thousandths of an inch in diameter and against an external impingement pin, which is also about six one-thousandths of an inch in diameter, although it is common for larger size impingement pins to be employed.
This creates droplets that are small. Small droplets are essentially unaffected by gravity. They evaporate in the air rather than cause localized wetting. Each droplet's heat of vaporization is removed from the ambient air, reducing the ambient air temperature. An array of 200 to 300 of these nozzles can cool a large area, even an outdoor area.
Wetting was always the problem. Not only does wetting mean that cooling isn't being done efficiently, wetting can actually be harmful in many applications, by leading to mildew and mold, and damaging perishables, etc. A nozzle the puts out any significant number of large particles causes wetting, limiting the uses of the cooling system. Wear was one reason why nozzles did not perform in service, but manufacturing irregularities have been a much greater factor. The wear characteristics of a nozzle were unimportant if the nozzle could not be put into service in the first place.
The closest prior art to the present invention is U.S. Pat. No. 4,869,430 to Good. This reference shows a fog nozzle and it teaches directly away from our invention. The Good reference, which relies upon extrusion technology, teaches the use of a long, narrow delivery channel to improve the quality of the stream of fluid issuing from the nozzle's orifice.
U.S. Pat. No. 1,940,171 to Huss teaches the use of a diamond orifice, but the Huss reference relies upon drilling, the only technology available at the time of the reference, and does not show an orifice on the order of magnitude of the present invention; that is, six one-thousands of an inch in diameter. Applicant is not aware of anyone, anywhere, who can drill a six one-thousandths of an inch hole in a diamond, ruby or sapphire.
In fact, in 1988, when the Good reference was filed, the fog nozzle industry was only barely capable of drilling such a hole in brass, and learning to drill stainless.
The device of the Huss reference differs in several important respects: